Organic light emitting diode substrate and preparation method thereof, and display panel

ABSTRACT

There provide an organic light emitting diode substrate and preparation method thereof and a display panel. The preparation method includes: forming a pixel defining layer which defines a pixel region and has a via hole on a base; forming an auxiliary electrode in the via hole; forming a capsule structure encapsulating a conductive liquid on the auxiliary electrode; expanding the capsule structure to be broken so as to enable the conductive liquid to form a connection electrode; and forming a first electrode covering the base, the first electrode being connected to the auxiliary electrode through the connection electrode. In the present disclosure, the connection electrode is formed through the capsule structure encapsulating the conductive liquid, so that the first electrode is connected to the auxiliary electrode through the connection electrode. The preparation process is simpler and the production cost is lower.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional of U.S. patent application Ser.No. 16/007,188, filed Jun. 13, 2018, now U.S. Pat. No. ______, whichclaims priority to Chinese Patent Application No. 201810006118.3, filedwith the State Intellectual Property Office on Jan. 3, 2018, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an organic light emitting diodesubstrate and preparation method thereof, and a display panel.

BACKGROUND

CRT (Cathode Ray Tube) displays have been gradually replaced by LCD(Liquid Crystal Display) devices and OLED (Organic Light Emitting Diode)display devices in the technical field of display. The OLED displaydevice is expected to become the core display in the next generation offlat panel display technology by virtue of its advantages of beingactive in light emitting, quick in response, wide in viewing angle, highin brightness and color saturation, low in cost, light, thin andflexible, etc. Based on light emitting directions, OLEDs are classifiedinto bottom-emission OLEDs (namely, emitting light downwards relative tothe substrates), top-emission OLEDs (namely, emitting light upwardsrelative to the substrates), and other OLEDs. As the top-emission OLEDhas the advantages of a high aperture ratio and color purity, easinessin achievement of a high resolution (Pixels per inch, (PPI)), and thelike, it has become a mainstream organic electroluminescent devicestructure at present.

The OLED is a current driving component mainly composed of a secondelectrode, a light emitting function layer, and a first electrode whichare sequentially away from a substrate. As a light emitting direction ofthe top-emission OLED is located at one side of the first electrode, thefirst electrode is required to have higher light transmittance andconductivity. The first electrode is generally made of a single metaland/or an alloy material with a low work function, so a lighttransmittance rate of the first electrode is smaller. Thus, in order toreduce the influence of the first electrode on the light emitting rate,the first electrode is required to be very thin. However, the resistanceof the thinner first electrode is larger, which will cause an obviousvoltage drop (IR Drop). As a result, emitted light is non-uniform due tonon-uniform voltage distribution on the first electrode, andaccordingly, power consumption is increased.

In order to solve the problem, a solution in which an auxiliaryelectrode is arranged on an array substrate had been provided. Accordingto the solution, the auxiliary electrode with a lower resistance isconnected to the first electrode to reduce the voltage drop and increasethe uniformity of emitted light.

SUMMARY

The present disclosure provides an organic light emitting diodesubstrate and preparation method thereof, and a display panel.

In a first aspect, there is provided an organic light emitting diodesubstrate, including a base, and a pixel defining layer which isconfigured to define a plurality of pixel regions on the base andcomprises a via hole; an auxiliary electrode whose orthographicprojection region on the base is located in an orthographic projectionregion of the via hole on the base; a connection electrode comprising aconductive liquid; and a first electrode connected to the auxiliaryelectrode through the connection electrode.

Optionally, the organic light emitting diode substrate further includes:at least one blocking structure whose orthographic projection region onthe base is located in an orthographic projection region of the via holeon the base, and the blocking structure is arranged to surround theauxiliary electrode.

Optionally, the distance from the surface of the blocking structure awayfrom the base to the base is a first distance; the distance from thesurface of the pixel defining layer away from the base to the base is asecond distance; and the first distance is shorter than the seconddistance.

Optionally, the surface of the blocking structure away from the base isconcave-convex.

Optionally, the organic light emitting diode substrate further includes:a second electrode and a light emitting function layer, wherein thesecond electrode is located in the pixel region; the light emittingfunction layer is located between the second electrode and the firstelectrode; and the connection electrode is located in the light emittingfunction layer.

Optionally, the distance from the surface of the blocking structure awayfrom the base to the base is a first distance; the distance from thesurface of the light emitting function layer away from the base to thebase is a third distance; and the first distance is longer than thethird distance.

Optionally, the thickness of the blocking structure in a directionperpendicular to the base is 10-100 nm.

Optionally, the at least one blocking structure comprises a plurality ofblocking structures arranged in a shape of concentric rings.

In another aspect, there is provided a reparation method of an organiclight emitting diode substrate, comprising: forming a pixel defininglayer which defines a pixel region and has a via hole on a base; formingan auxiliary electrode in the via hole; forming a capsule structureencapsulating a conductive liquid on the auxiliary electrode; expandingthe capsule structure to be broken so as to enable the conductive liquidto form a connection electrode; and forming a first electrode coveringthe base, the first electrode being connected to the auxiliary electrodethrough the connection electrode.

Optionally, after forming the pixel defining layer which defines thepixel region and has the via hole on the base, the method furthercomprises: forming a blocking structure in the via hole on the base, theblocking structure surrounding the auxiliary electrode.

Optionally, the distance from the surface of the blocking structure awayfrom the base to the base is a first distance, the distance from thesurface of the capsule structure away from the base to the base is afourth distance, and the first distance is longer than the fourthdistance.

Optionally, after forming the pixel defining layer which defines thepixel region and has the via hole on the base, the method furthercomprises: forming a second electrode located in the pixel region on thebase; and forming a light emitting function layer on the base with thecapsule structure, the light emitting function layer being locatedbetween the first electrode and the second electrode, and the connectionelectrode being located in the light emitting function layer.

Optionally, the capsule structure comprises the conductive liquid and acasing encapsulating the conductive liquid; the casing is made of anepoxy resin or a polyacrylic resin; and the conductive liquid is aliquid metal, a metal oxide conductive liquid, or a nanoparticleconductive liquid.

Optionally, expanding the capsule structure to be broken so as to enablethe conductive liquid to form the connection electrode comprises:expanding the via hole to enable the capsule structure to be expandedafter being heated and to generate a crack on the light emittingfunction layer in the via hole; and allowing the conductive liquid toflow onto the surface of the auxiliary electrode after the capsulestructure is broken and to flow onto the surface of the light emittingfunction layer along the crack, so as to form the connection electrodeconnected to the auxiliary electrode in the light emitting functionlayer.

Optionally, the expanding comprises heating.

Optionally, the expanding comprises heating and light irradiation.

Optionally, a heating temperature during the heating is less than 100°C.

Optionally, in the heating and light irradiation, an irradiation lightintensity is 100-5000 mJ/cm².

Optionally, in the heating and light irradiation, near ultraviolet lightis used in the light irradiation.

In yet another aspect, there is provided a display panel, comprising anorganic light emitting diode substrate, wherein the organic lightemitting diode substrate comprises: a base; a pixel defining layer whichis configured to define a plurality of pixel regions on the base andcomprises a via hole; an auxiliary electrode whose orthographicprojection region on the base is located in an orthographic projectionregion of the via hole on the base; a connection electrode comprising aconductive liquid; and a first electrode connected to the auxiliaryelectrode through the connection electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of a preparation method of an organic lightemitting diode substrate according to an embodiment of the presentdisclosure;

FIG. 2 is a schematic diagram after a pattern of an array structurelayer is formed according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram after a pixel definition layer is formedaccording to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram after a second electrode and an auxiliaryelectrode are formed according to an embodiment of the presentdisclosure;

FIG. 5 is a schematic diagram after a blocking structure is formedaccording to an embodiment of the present disclosure;

FIG. 6 is another schematic diagram after a blocking structure is formedaccording to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram after a capsule structure is formedaccording to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram after a light emitting function layer isformed according to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram after a capsule structure breaks accordingto an embodiment of the present disclosure; and

FIG. 10 is a schematic diagram after a first electrode is formedaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure will be described in further detail withreference to the accompanying drawings and embodiments. The followingembodiments are intended to illustrate the present disclosure, ratherthan limit the scope of the present disclosure. It should be noted that,without conflicts, the embodiments of the present disclosure and thefeatures in the embodiments may be combined in any manner.

In order to solve the problem that a connection process of a firstelectrode and an auxiliary electrode is poor in contact, high inproduction cost, likely to cause a pixel defect, and complex, thepresent disclosure provides a preparation method of an organic lightemitting diode substrate.

FIG. 1 is a flow chart of a preparation method of an organic lightemitting diode substrate according to an embodiment of the presentdisclosure. As shown in FIG. 1, the preparation method of the organiclight emitting diode substrate comprises:

forming a pixel defining layer which defines a pixel region and has avia hole on a base in step S1;

forming an auxiliary electrode in the via hole in step S2;

forming a capsule structure encapsulating a conductive liquid on theauxiliary electrode in step S3;

expanding the capsule structure to be broken so as to enable theconductive liquid to form a connection electrode in step S4; and

forming a first electrode covering the base, the first electrode beingconnected to the auxiliary electrode through the connection electrode instep S5.

After step S1, the preparation method of the organic light emittingdiode substrate may further comprise: forming a blocking structure inthe via hole on the base, wherein the blocking structure is arranged tosurround the auxiliary electrode.

Optionally, the distance from the surface of the blocking structure awayfrom the base to the base is a first distance; the maximum distance fromthe surface of the capsule structure away from the base to the base is afourth distance; and the first distance is longer than the fourthdistance.

Optionally, after step S1, the preparation method of the organic lightemitting diode substrate may further comprise: forming a secondelectrode located in the pixel region on the base; and forming a lightemitting function layer on the base with the capsule structure, whereinthe light emitting function layer is located between the first electrodeand the second electrode; and the connection electrode is located in thelight emitting function layer.

It should be noted that one of the first electrode and the secondelectrode may be an anode, and the other electrode may be a cathode. Forexample, the first electrode is a cathode and the second electrode is ananode; or the first electrode is an anode and the second electrode is acathode, which is not limited by the embodiment of the presentdisclosure.

The capsule structure formed in step S3 comprises the conductive liquidand a casing encapsulating the conductive liquid. The casing may be madeof an epoxy resin or a polyacrylic resin. The conductive liquid may be aliquid metal, a metal oxide conductive liquid, or a nanoparticleconductive liquid.

Alternatively, step S4 may comprise:

expanding the via hole to enable the capsule structure to be expandedafter being heated and to generate a crack on the light emittingfunction layer in the via hole; and allowing the conductive liquid toflow onto the surface of the auxiliary electrode after the capsulestructure is broken and to flow onto the surface of the light emittingfunction layer along the radial crack, so as to form the connectionelectrode connected to the auxiliary electrode in the light emittingfunction layer.

Optionally, the expanding comprises heating.

Optionally, a heating temperature during the heating is less than 100°C.

Optionally, the expanding comprises heating and light irradiation.

Optionally, in the heating and light irradiation, an irradiation lightintensity is 100-5000 mJ/cm².

Optionally, near ultraviolet light is used in the light irradiation.

Optionally, the wavelength of light used in the light irradiation is 395nm.

In the preparation method of the organic light emitting diode substrateprovided by the embodiments of the present disclosure, the connectionelectrode is formed through the capsule structure encapsulating theconductive liquid, so that the first electrode is connected to theauxiliary electrode through the connection electrode. The preparationprocess is simpler and the production cost is lower. Moreover, theconnection reliability between the first electrode and the auxiliaryelectrode is higher. Compared with the prior art using a laser method,the preparation method simplifies the process, overcomes the defect ofpoor contact, and avoids a pixel defect caused by a carbide after laserirradiation.

The technical solutions of the embodiments of the present disclosure arefurther described below through the preparation process of the organiclight emitting diode substrate.

FIGS. 2-10 are schematic views showing the preparation of an organiclight emitting diode substrate according to an embodiment of the presentdisclosure. The term “patterning process” in the embodiment of thepresent disclosure comprises depositing a film layer, coating aphotoresist, exposing a mask, developing, etching, peeling thephotoresist, and other steps, and is an existing mature preparationprocess. The depositing may be implemented through a known process suchas sputtering, vacuum evaporation and chemical vapor deposition. Thecoating may be implemented through a known coating process. The etchingmay be implemented through a known method. Those are not specificallylimited herein.

(1) As shown in FIG. 2, a pattern of an array structure layer 12 isformed on a base 11 through a patterning process. In the embodiment ofthe present disclosure, the array structure layer 12 comprises a thinfilm transistor (TFT). The structure and a preparation process of thearray structure layer are the same as those in the prior art, which arenot limited in this embodiment of the present disclosure. For example,the preparation process may comprise: cleaning a base first; and thenpreparing a gate electrode, an insulating layer, an active layer, sourceand drain electrodes, and a passivation layer on the base through thepatterning process. The base may be made of glass, quartz, polyethyleneterephthalate (PET), a surface-treated polymer soft film, or the like.The thin film transistor may be of a bottom gate structure or a top gatestructure, and may be an amorphous silicon (a-Si) thin film transistor,a low-temperature polysilicon (LTPS) thin film transistor or an oxidethin film transistor, which is not specifically limited herein. Thedrain electrode of the thin film transistor is electrically connected toa second electrode. Each row of the thin film transistor is turned ongradually through a gate scanning signal. Voltage data is transmitted tothe second electrode through the thin film transistor. The secondelectrode cooperates with the first electrode to generate a voltagedifference for driving a light emitting function layer to emit light soas to achieve independent light emitting.

(2) A pixel defining layer is formed on the base with the abovestructure through the patterning process. Forming the pixel defininglayer comprises: depositing or coating a pixel defining thin film on thebase with the above structure, wherein the pixel defining thin film maybe made of polyimide, acrylic, or polyethylene terephthalate; andexposing and developing the pixel defining thin film through amonochrome mask plate to form the pixel defining layer 15 defining apixel region X (as shown in FIG. 3). A via hole Y is formed in the pixeldefining layer 15.

(3) A second electrode and an auxiliary electrode are formed on the basewith the above structure. Forming the second electrode and the auxiliaryelectrode comprises: depositing a first metal thin film or a firsttransparent conductive thin film on the base with the above structure,and forming the second electrode 13 and the auxiliary electrode 14through the patterning process, as shown in FIG. 4. It should be notedthat the base is provided with a plurality of pixel regions X. Thesecond electrode 13 may be located in the pixel region X; and theauxiliary electrode may be located in the via hole Y between the pixelregions X. That is, an orthographic projection region of the auxiliaryelectrode on the base is located within that of the via hole on thebase. As shown in FIG. 0.3, there are two pixel regions X and one viahole Y located between the two pixel regions X. The pixel region X is alight emitting region defined by the pixel defining layer. The secondelectrode 13 is exposed in the pixel region X. The via hole Y is aregion which is formed in the pixel defining layer and which isconfigured to connect the first electrode and the auxiliary electrode.The auxiliary electrode 14 is exposed in the via hole Y. It should benoted that in the embodiment of the present disclosure, forming theauxiliary electrode and the second electrode through one-step patterningprocess is taken as an example. In practical applications, the auxiliaryelectrode and the second electrode may also be formed through twopatterning processes, respectively, which is not limited by theembodiment of the present disclosure.

The first transparent conductive thin film may be made of an indium tinoxide (ITO), an indium zinc oxide (IZO), or the like. The first metalthin film may be made of any of metals such as magnesium (Mg), silver(Ag), aluminum (Al) and copper (Cu), or an alloy of the above metals, ora composite layer of the above metals. The embodiment of the presentdisclosure does not limit a pattern of the auxiliary electrode. Forexample, the pattern of the auxiliary electrode may be block-shaped,strip-shaped, or grid-shaped. The auxiliary electrode 14 may beconnected to a printed circuit in a non-display region on the basethrough a lead.

Optionally, after the pixel defining layer is formed, as shown in FIG.5, a blocking structure 16 may also be formed in the via hole in thearray structure layer. The blocking structure 16 is also located in thevia hole in the pixel defining layer, and is configured to protect thepixel region when the connection electrode is formed, so as to avoid apixel defect likely caused by the preparation process.

Optionally, the blocking structure 16 may be ring-shaped and is arrangedto surround the auxiliary electrode. A plurality of blocking structuresin a shape of concentric rings may be formed in the via hole. In FIG. 5,for example, the surface of the blocking structure away from the base isa plane. In practical applications, as shown in FIG. 6, the surface ofthe blocking structure away from the base may also be concave-convex(only a ring-shaped blocking structure is shown in FIG. 6).

The blocking structure has a cross section perpendicular to the base.The cross section may be rectangular, triangular or trapezoidal. InFIGS. 5 and 6, only the rectangular cross section is taken as anexample. Optionally, the aspect ratio of the rectangle may be 10:1 to1:10.

(4) A capsule structure is formed on the auxiliary electrode. Formingthe capsule structure comprises: spraying the capsule structure 17 mixedin a solution in the via hole through ink jet printing (IJP) on the basewith the above structure, so as to form the capsule structure 17 on theauxiliary electrode 14, as shown in FIG. 7. The solution may be resin.The capsule structure 17 comprises a conductive liquid and a casingencapsulating the conductive liquid. The casing may be made of an epoxyresin or a polyacrylic resin, has an expansion characteristic, and mayexpand to be broken during expanding. The expanding may compriseheating, or may comprise heating and light irradiation. The conductiveliquid may be a liquid single metal such as mercury (Hg) or gallium(Ga), or a liquid metal alloy containing mercury or gallium, or a metaloxide conductive liquid, or a nanoparticle conductive liquid.

In the embodiment of the present disclosure, the capsule structure 17may be spherical or ellipsoidal. Optionally, the capsule structure 17 isellipsoidal, so that the fixation of the capsule structure 17 isconvenient. Here, a long axis of the capsule structure 17 is parallel toor nearly parallel to the base; and a short axis of the capsulestructure 17 is 10-100 nm. Optionally, referring to FIG. 7, the distancefrom the surface of the blocking structure 16 away from the base 11 tothe base 11 is a first distance D1; and the maximum distance from thesurface of the capsule structure 17 away from the base 11 to the base 11is a fourth distance D4. The first distance D1 is longer than the fourthdistance D4. That is, the distance from the upper end surface of thecapsule structure to the surface of the base is shorter than thedistance from the upper end surface of the blocking structure to thesurface of the base. One capsule structure 17 or a plurality of capsulestructures 17 may be arranged in each via hole.

(5) A light emitting function layer is formed on the base with the abovestructure. Forming the light emitting function layer comprises: formingthe light emitting function layer 18 on the base with the abovestructure through coating, spin coating, or ink jet printing. The lightemitting function layer 18 is formed in the pixel region and the viahole, as shown in FIG. 8. In the pixel region, the light emittingfunction layer 18 covers the second electrode 13. In the via hole, thelight emitting function layer 18 covers the capsule structure 17. Thedistance from the surface of the blocking structure 16 away from thebase 11 to the base 11 may be the first distance D1. The distance fromthe surface of the pixel defining layer 15 away from the base 11 to thebase 11 may be a second distance D2. The distance from the surface ofthe light emitting function layer 18 away from the base 11 to the base11 is a third distance D3. The first distance D1 is shorter than thesecond distance D2, and is longer than the third distance D3. That is,the distance from the upper end surface of the light emitting functionlayer 18 to the surface of the base is longer than the distance from theupper end surface of the capsule structure to the surface of the base,but is shorter than the distance from the upper end surface of theblocking structure to the surface of the base.

For example, the light emitting function layer 18 may comprise a holeinjection layer (HIL), a hole transport layer (HTL), an electronblocking layer (EBL), an organic light emitting layer (EML), a holeblocking layer (HBL), an electron transport layer (ETL) and an electroninjection layer (EIL) which are sequentially arranged in the directionfrom the second electrode toward the first electrode. Each layer may bemade of an organic small molecule material, an organic polymer material,an inorganic material, a composite dopant material, or the like. Theorganic light emitting layer may be a combination of a red lightemitting layer (REML), a green light emitting layer (GEML) and a bluelight emitting layer (BEML), or may be a white light emitting layer(WEML) only. The structure of the light emitting function layer may alsobe other forms. The light emitting function layer may also be formed byother colors of light emitting layers, which is not limited herein.

(6) The capsule structure is subjected to expansion. For example, thebase with the above structure is heated (or heated and light-irradiated)to enable the capsule structure 17 to be expanded through heat. Throughthe expanded capsule structure 17, a radial crack taking the capsulestructure 17 as the center appears on the light emitting function layer18 covering the capsule structure 17. Then, the capsule structure 17expanding to a certain degree breaks; and the conductive liquid in thecapsule structure 17 flows out from the broken casing, and flows in theradial crack of the light emitting function layer 18. A part of theconductive liquid flows onto the surface of the auxiliary electrode 14away from the base, and the other part of the conductive liquid flowsout of the light emitting function layer 18 to flow onto the surface ofthe light emitting function layer 18 away from the base along the crack,so as to form a connection electrode 19 which is connected to theauxiliary electrode 14 and covers the surface of the light emittingfunction layer 18 in the via hole, as shown in FIG. 9. In the embodimentof the present disclosure, a heating temperature during heating may beless than 100° C. In the heating and light irradiation, near ultravioletlight (for example, light with a wavelength of 395 nm) is used in thelight irradiation; the irradiation light intensity is 100-5000 mJ/cm²;and the heating temperature is less than 100° C. In a practicalimplementation, a corresponding heating time and irradiation time may beset according to specifications of adopted heating equipment and lightirradiation equipment, so as to obtain the required heating temperatureand irradiation light intensity.

(7) A first electrode is formed on the base with the above structure.Forming the first electrode comprises: depositing a second metal thinfilm or a second transparent conductive thin film on the base with theabove structure to form the first electrode 20 which is connected to theauxiliary electrode 14 through the connection electrode 19 in the viahole, as shown in FIG. 10. Generally, the first electrodes are connectedto the same power supply voltage, in order to simplify the structure, afull surface electrode may be used as the first electrodes. The firsttransparent conductive thin film may be made of ITO, IZO, or the like.The second metal thin film may be made of any of metals such asmagnesium (Mg), silver (Ag), aluminum (Al), copper (Cu) and lithium(Li), or an alloy of the above metals, or a composite layer of the abovemetals.

Subsequently, the preparation process further comprises a step ofpreparing an encapsulating layer on the base with the above structure,or a step of preparing a color film layer and the encapsulating layer onthe base with the above structure, which is not repeated herein.

In order to connect the first electrode with the auxiliary electrodethrough the connection electrode and avoid the influence of the abovepreparation process on the pixel region, the relationship among thepixel defining layer, the blocking structure, the light emittingfunction layer and the capsule structure in the embodiments of thepresent disclosure is that the blocking structure is lower than thepixel defining layer;

the capsule structure is lower than the blocking structure; and thelight emitting function layer is higher than the capsule structure butis lower than the blocking structure. Exemplarily, the thickness of theblocking structure 16 in a direction perpendicular to the base is 10-100nm.

In the embodiment of the present disclosure, the blocking structure isconfigured to protect the light emitting function layer in the pixelregion from being influenced by a process for preparing the connectionelectrode. When the capsule structure expands and breaks, the conductiveliquid flows onto the surface of the light emitting function layer. Asthe blocking structure is higher than the light emitting function layerand the surface of the blocking structure is concave-convex, the speedof the conductive liquid flowing to the pixel defining layer is sloweddown, and accordingly, the length that the conductive liquid flows tothe pixel defining layer is increased. Even if a part of the conductiveliquid flows to the pixel defining layer, it can be ensured that theconductive liquid will not flow into the pixel region as the pixeldefining layer is higher than the blocking structure. Thus, a pixeldefect likely caused by the preparation process is effectively avoided.In addition, the blocking structure can also prevent the crack in thelight emitting function layer from expanding to the pixel region whenthe capsule structure expands.

In the structure of the top-emission OLED substrate provided by theembodiment of the present disclosure, the first electrode is connectedto the auxiliary electrode there below through the conductive liquid inthe via hole of the pixel defining layer. On one hand, a parallelstructure is formed after the first electrode and the auxiliaryelectrode are connected, so that a surface resistance of the thinnerfirst electrode is reduced, and a problem of voltage drop of the firstelectrode is solved. Therefore, the voltage distribution of the firstelectrodes is uniform; and thus, an obvious non-uniform light emittingphenomenon of the top-emission OLED is avoided. On the other hand, asthe auxiliary electrode is arranged in a region where the via hole islocated in the pixel defining layer and the connection electrode forconnecting the auxiliary electrode and the first electrode are alsoarranged in this region, the connection among the auxiliary electrode,the connection electrode and the first electrode does not occupy a lightemitting region (namely, the pixel region), and accordingly, does notaffect an aperture ratio of a pixel. In an existing structure,generally, the first electrodes adopt an overall thin film structure.Since the thinner film is larger in resistance, a peripheral drivingcircuit needs to apply a higher voltage so as to ensure voltages of thefirst electrodes located in a central display region. In addition,voltages on the first electrodes are also different due to differentlocations of pixel regions, resulting in non-uniform voltagedistribution. In the embodiment of the present disclosure, the auxiliaryelectrode is provided; and the thicker auxiliary electrode functions asa transmission line. The voltage of the peripheral driving circuit isguided near to each first electrode and then is transmitted to the firstelectrode, so that the voltages on all the first electrodes are thesame. Thus, the voltage distribution is uniform, and the brightnessuniformity is higher. Meanwhile, problems of voltage rise and increasedpower consumption are solved. The first electrode can be designed to bevery thin as the auxiliary electrode functioning as a transmission lineis arranged, so as to improve the light transmittance to the greatestextent.

It can be seen from the above preparation process that the connectionelectrode for connecting the first electrode and the auxiliary electrodeprovided by the embodiment of the present disclosure is prepared byheating the capsule structure. As the capsule structure is formedthrough ink jet printing, an additional mask plate is eliminated. Thepreparations of other film layers are the same as those in the priorart. Thus, the preparation method provided by the embodiments of thepresent disclosure has minor modifications to the existing process, issimpler in preparation process, more convenient to implement, lower inproduction cost, and especially suitable for large-size OLED panels, andthus has a wider application prospect. Meanwhile, the conductive liquidformed after heating the capsule structure has a high penetrating power;the connection between the connection electrode and the auxiliaryelectrode is reliable; the flatness of the conductive liquid formed onthe surface of the light emitting function layer is excellent; theconnection between the connection electrode and the first electrode isreliable; and poor connection between the first electrode and theauxiliary electrode is avoided. Compared with an existing laser method,defects such as a complex process, high production cost and poor contactare overcome; and moreover, a pixel defect caused by a carbide afterlaser irradiation is avoided.

As shown in FIG. 10, an organic light emitting diode substrate preparedby the preparation method provided by the embodiments of the presentdisclosure comprises:

a base 11;

an array structure layer 12 arranged on the base 11; and

a second electrode 13, an auxiliary electrode 14, a pixel defining layer15, at least one blocking structure 16, a connection electrode 19 and alight emitting function layer 18 which are arranged on the arraystructure layer 12, wherein the pixel defining layer 15 is configured todefine a plurality of pixel regions on the base 11, and comprises a viahole; the second electrode 13 is located in the pixel region X on thebase; both the auxiliary electrode 14 and the blocking structure 16 arelocated in the via hole; the blocking structure 16 is arranged tosurround the auxiliary electrode 14; and the connection electrode 19 isarranged on the auxiliary electrode 14, is located in the light emittingfunction layer 18, and comprises a conductive liquid.

The organic light emitting diode further comprises a first electrode 20arranged on the light emitting function layer 18. The first electrode 20is connected to the auxiliary electrode 14 through the connectionelectrode 19. The light emitting function layer 18 is located betweenthe second electrode 13 and the first electrode 20.

Optionally, the at least one blocking structure 16 comprises a pluralityof blocking structures 16 arranged in a shape of concentric rings. Thedistance from the surface of the blocking structure 16 away from thebase 11 to the base 11 is a first distance. The distance from thesurface of the pixel defining layer 15 away from the base 11 to the base11 is a second distance. The distance from the surface of the lightemitting function layer 18 away from the base 11 to the base 11 is athird distance. The first distance is longer than the third distance andis shorter than the second distance. The surface of the blockingstructure 16 away from the base 11 is concave-convex. The thickness ofthe blocking structure 16 in a direction perpendicular to the base 11 is10-100 nm.

Based on the technical conception of the embodiments of the presentdisclosure, the OLED substrate and the preparation method thereofdescribed above may be expanded to form a plurality of related technicalsolutions.

For example, the second electrode and the auxiliary electrode may beformed in different patterning processes according to different arraystructure layers. For instance, after a gate electrode, an insulatinglayer, an active layer, source and drain electrodes, and a passivationlayer are prepared, the second electrode (a pixel electrode) is directlyformed; then, a planarization layer is formed; and an auxiliaryelectrode is formed on the planarization layer.

For another example, when the pixel defining layer is formed, theblocking structure may not be formed if the height of the pixel defininglayer is enough to protect the light emitting function layer in thepixel region from being influenced by a process for preparing theconnection electrode. In addition, patterns of the pixel defining layerand the blocking structure may be simultaneously formed or respectivelyformed. When the patterns of the pixel defining layer and the blockingstructure are respectively formed, the blocking structure may be formedin the via hole by spraying an ester material through IJP after thepixel defining layer is formed. Or, the blocking structure may be formedthrough partial deposition and etching, and may be made of a siliconnitride (SiNx), a silicon oxide (SiOx), or the like.

The embodiments of the present disclosure further provide a displaypanel comprising the organic light emitting diode substrate with thetop-emission structure provided by the above embodiments. The displaypanel may be a cell phone, a tablet computer, a TV, a display, anotebook computer, a digital photo frame, a navigator, or any otherproduct or component having a display function.

In the description of the embodiments of the present disclosure, itshould be understood that orientations or position relationshipsindicated by the terms “middle”, “upper”, “lower”, “front”, “rear”,“vertical”, “horizontal”, “top”, “bottom”, “internal”, “external”, andthe like are those based on the drawings, and are merely configured todescribe the present disclosure conveniently and simplify thedescription, rather than indicating or implying that the referred deviceor element must has a specific orientation and must be configured andoperated at the specific orientation. Therefore, they should not beconstrued as limiting the present disclosure.

In the description of the embodiments of the present disclosure, itshould be noted that the terms “mounted”, “connected with” and“connected to” should be broadly understood unless explicitly defined orlimited otherwise. For example, they may refer to a fixed connection,detachable connection or integrated connection, or may be a mechanicalconnection or electrical connection, or may refer to a direct connectionor an indirect connection via an intermediary, or may be an internalcommunication of two elements. An ordinary person skilled in the art mayunderstand the specific meanings of the above terms in the presentdisclosure based on specific situations.

Although the embodiments disclosed by the present disclosure are shownas above, the contents are merely embodiments for facilitating theunderstanding of the present disclosure and are not intended to limitthe present disclosure. Any person skilled in the art may make anymodifications and variations to the implementations in the forms anddetails without departing from the spirit and scope disclosed in thepresent disclosure. The patent protection scope of the presentdisclosure still should be subject to the protection scope defined bythe claims.

What is claimed is:
 1. An organic light emitting diode substrate,comprising: a base; a pixel defining layer which is configured to definea plurality of pixel regions on the base and comprises a via hole; anauxiliary electrode whose orthographic projection region on the base islocated in an orthographic projection region of the via hole on thebase; a connection electrode comprising a conductive liquid; and a firstelectrode connected to the auxiliary electrode through the connectionelectrode.
 2. The organic light emitting diode substrate of claim 1,further comprising: at least one blocking structure whose orthographicprojection region on the base is located in an orthographic projectionregion of the via hole on the base, the blocking structure beingarranged to surround the auxiliary electrode.
 3. The organic lightemitting diode substrate of claim 2, wherein the distance from thesurface of the blocking structure away from the base to the base is afirst distance; the distance from the surface of the pixel defininglayer away from the base to the base is a second distance; and the firstdistance is shorter than the second distance.
 4. The organic lightemitting diode substrate of claim 2, wherein the surface of the blockingstructure away from the base is concave-convex.
 5. The organic lightemitting diode substrate of claim 2, further comprising: a secondelectrode and a light emitting function layer, wherein the secondelectrode is located in the pixel region; the light emitting functionlayer is located between the second electrode and the first electrode;and the connection electrode is located in the light emitting functionlayer.
 6. The organic light emitting diode substrate of claim 5, whereinthe distance from the surface of the blocking structure away from thebase to the base is a first distance; the distance from the surface ofthe light emitting function layer away from the base to the base is athird distance; and the first distance is longer than the thirddistance.
 7. The organic light emitting diode substrate of claim 2,wherein the thickness of the blocking structure in a directionperpendicular to the base is 10-100 nm.
 8. The organic light emittingdiode substrate of claim 2, wherein the at least one blocking structurecomprises a plurality of blocking structures arranged in a shape ofconcentric rings.
 9. A display panel, comprising an organic lightemitting diode substrate, wherein the organic light emitting diodesubstrate comprises: a base; a pixel defining layer which is configuredto define a plurality of pixel regions on the base and comprises a viahole; an auxiliary electrode whose orthographic projection region on thebase is located in an orthographic projection region of the via hole onthe base; a connection electrode comprising a conductive liquid; and afirst electrode connected to the auxiliary electrode through theconnection electrode.